In recent years, electric automobiles that employ batteries for their drive force and hybrid cars that employ batteries for a portion of their drive force have become widespread. When such an automobile is traveling while using its battery for drive force, the level of drive noise within the passenger compartment is dramatically lower as compared to the case of a prior art gasoline automobile. As a result, it may become impossible appropriately to experience a realistic traveling feeling based upon the engine sound, as is experienced in the case of a gasoline automobile. In many cases the state of affairs is not desirable from the standpoints of safe driving and of enjoyment of a comfortable driving feeling.
By this, a technique has been proposed of generating engine-like pseudo sound in the interior of the passenger compartment corresponding to the conditions of traveling of the vehicle (refer to Patent Document #1, hereinafter termed the “prior art example”). With the prior art technique, when generating engine-like pseudo sound on the basis of traveling information such as engine rotating speed, throttle opening amount (accelerator opening amount), vehicle speed and so on, the audio volume of the sound within the passenger compartment is adjusted according to the result of sound pickup.